1. Field of the Invention
The present invention relates to a scroll compressor, and particularly, to a an oil discharge preventing apparatus of a scroll compressor capable of reducing the number of components and simplifying assembling processes as well as minimizing an oil leakage to the exterior.
2. Description of the Conventional Art
In general, compressors are such devices for compressing a refrigerant by converting electric energy into kinetic energy. Such compressors construct a refrigeration system.
The compressors are divided into a rotary compressor, a reciprocal compressor, a scroll compressor, and the like, according to a mechanism for compressing a refrigerant.
The scroll compressor compresses the refrigerant by orbiting in a state that two scrolls are engaged with each other. The scroll compressor can be classified into a low pressure type in which the inside of a casing is maintained in a low pressure state (i.e., a suction pressure state), and a high pressure type in which the inside of the casing is maintained in a high pressure state (i.e., a discharge pressure state).
FIG. 1 is a sectional view showing a part of a compressing device of the scroll compressor.
As shown in the drawing, the scroll compressor includes: a casing 10 having a suction pipe 11 and a discharge pipe 12; a main frame fixed into the casing 10; a fixing scroll 30 fixedly-coupled to an upper side of the main frame 20; an orbiting scroll 40 positioned between the fixing scroll 30 and the main frame 20 so as to be engaged with the fixing scroll 30 to thusly orbit; an oldham ring 50 positioned between the orbiting scroll 40 and the main frame 20, for preventing a rotation of the orbiting scroll 40; a driving motor M fixedly-coupled to the casing 10 with a constant interval from the main frame 20, for generating a driving force; and a rotary axis 60 for transferring the driving force of the driving motor M to the orbiting scroll 40.
The suction pipe 11 is connected to an inlet 31 formed in the fixing scroll 30, and the discharge pipe 12 is located at a lower side of the fixing scroll 30. A bottom surface of the casing 10 is filled with oil.
The main frame 20 includes a frame body portion 21 having a particular shape, an axial insertion opening 22 formed in the frame body portion 21 and through which the rotary axis 60 is inserted, and a boss insertion groove 23 formed with an inner diameter greater than that of the axial insertion opening 22, extending upwardly from the axial insertion opening 22.
The fixing scroll 30 includes a body portion 32 formed in a particular shape, a wrap 33 formed at one surface of the body portion 32 in an involute curve having constant thickness and height, a discharge hole 34 formed through the middle of the body portion 32, and an inlet 31 formed at one side of the body portion 32.
The orbiting scroll 40 includes a disc portion 41 having constant thickness and area, a wrap 42 formed at one surface of the disc portion 41 in the involute curve having constant thickness and height, and a boss portion 43 formed in the middle of the other side of the disc portion 41.
The wrap 42 of the orbiting scroll 40 is engaged with the wrap 33 of the fixing scroll 30, and the boss portion 43 thereof is inserted into the boss insertion groove 23 of the main frame 20.
The rotary axis 60 has an eccentric portion 61 therein. One side of the rotary axis 60 is penetratingly inserted into the axial insertion opening 22 of the main frame 20, and thus its eccentric portion 61 is coupled to the boss portion 43 of the orbiting scroll 40.
The driving motor M includes a stator 70 fixed inwardly to the casing 10, and a rotor 80 rotatably coupled to the inside of the stator 70.
The scroll compressor having such construction will be operated as follows.
When power is applied to the scroll compressor, the rotor 80 rotates by interaction between the stator 70 and the rotor 80 constructing the driving motor M. A rotation force of the rotor 80 is then transferred to the orbiting scroll 40 through the rotary axis 60. As the rotation force of the rotary axis 60 is transferred to the orbiting scroll 40, the orbiting scroll 40 which is coupled to the eccentric portion 61 of the rotary axis 60 orbits centered upon an axial center of the rotary axis 60.
While the orbiting scroll 40 is engaged with the fixing scroll 30 to perform an orbiting motion, volumes of a plurality of compression pockets P formed by the wrap 42 of the orbiting scroll 40 and the wrap 33 of the fixing scroll 30 are changed, so as to suck, compress and discharge a refrigerant. At this time, the refrigerant is sucked into the compression pockets P through the suction pipe 11 and the inlet 31. The refrigerant compressed in the compression pockets P is discharged into the casing 10 through the discharge hole 34.
The compressed refrigerant discharged into the casing 10 flows in the casing 10 and circulates a refrigeration system through the discharge pipe 12.
The oil filled in the bottom of the casing 10, on the other hand, is pumped through an oil flow path 62 formed in the rotary axis 60 by the rotation of the rotary axis 60, and thus supplied between components (parts) which generate a relative motion with one another. The oil supplied between the components generating the relative motion with one another is returned to the bottom of the casing 10.
While such scroll compressor is driven, in the process that the oil filled in the bottom of the casing 10 is supplied between the components generating the relative motion and returned to the bottom of the casing 10, some parts of oil flow into the refrigeration system through the discharge pipe 12 together with the compressed refrigerant which flows in the casing 10. As a result, a lack of oil inside the casing may occur, which causes abrasion between components generating the relative motion. In addition, the oil in the casing 10 flows into the refrigeration system, which causes decrease of efficiency of the refrigeration system.
Therefore, it is one of important tasks to restrict the oil in the casing 10 from being leaked to the outside of the casing 10, researches for which have been executed.
As one of structures introduced in such researches and developments, as shown in FIGS. 1 and 2, a cylindrical oil guide 90 is provided at a lower portion of the main frame 20, and the oil guide 90 is fixedly-coupled to the rotor 80 constructing the driving motor by a bolt 100.
The oil guide 90 includes a cylindrical portion 91 having a constant length, and a supporting portion 92 coupled onto the middle of an inner wall of the cylindrical portion 91 with a particular area, and a plurality of penetration holes 93 formed through the supporting portion 92
The oil guide 90 is coupled to the rotor 93 to be fixedly-coupled to a balance weight 110 for maintaining a balance upon rotating. The balance weight 110 is fixed to an upper end ring 81 constructing the rotor 80.
The balance weight 110 includes; a stator 111 formed in a ring shape with particular thickness and width, and of which one part is open; a weight portion 112 extending upwardly to one side of the stator 111 by a particular height; two position fixing holes 113 formed through (penetratingly formed in) the stator 111; and a plurality of screw holes 114 formed in the weight portion 112.
The rotor 80 includes a core 82 having a certain length, and upper end ring 81 and lower end ring (not shown) which are fixed to both side surfaces of the core 82, respectively.
The upper end ring 81 coupled to an upper surface of the core 82 includes a ring porting E1 having particular thickness and width and an outer diameter corresponding to that of the core 82, and fixing protrusions E2 protrudingly extending from one surface of the ring portion E1.
The fixing protrusions E2 of the upper end ring 81 are inserted into the position fixing holes 113 of the balance weight 110, respectively. The balance weight 110 is coupled to the upper end ring 81 of the rotor 80 by caulking ends of the fixing protrusions E2 of the upper end ring 81. The balance weight 110 is inserted into the oil guide 90. The supporting portion 92 of the oil guide 90 is supported on the upper surface of the weight portion 112 of the balance weight 110. Bolts 100 are coupled to the penetration holes 93 of the oil guide 90 and the screw holes 114 of the balance weight 110, respectively. At this time, a lower surface of the oil guide 90 is contact with an upper surface of the upper end ring 81.
Unexplained reference symbol 71 denotes a lamination body, and 72 denotes a coil winding.
An operation of such structure will now be explained.
Parts of oil spread toward the upper end of the rotary axis 60 through the oil flow path 62 of the rotary axis 60 flows downwardly through the boss insertion groove 23 and the axial insertion opening 22. At this time, the oil is spread (shattered) by a centrifugal force of the rotary axis 60. The spread oil is collected by the oil guide 90 and flows downwardly. The oil flowing along the oil guide 90 is returned to the bottom of the casing 10 through an oil flow passage F formed between the rotor 80 and the rotary axis 60. Thus, the oil guide 90 collects the oil spread into the casing to guide the oil to the bottom of the casing 10. As a result, the oil leakage to the outside of the casing 10 together with the refrigerant can be minimized.
However, in such oil discharge preventing apparatus, after the upper end ring 81 of the rotor 80 and the balance weight 110 are coupled to each other by the caulking process, the oil guide 90 and the balance weight 110 are fastened to each other by a plurality of bolts 100, which may cause increase of the number of construction components and complication of assembling process, thereby resulting in increase of fabrication cost and decrease of assembling productivity.
Furthermore, a gap may generated between the oil guide 90 and the upper end ring 81 by processing tolerance or assembling tolerance when the balance weight 110 is coupled to the oil guide 90. The oil may be leaked through the gap to be spread into the casing 10, thereby being leaked to the outside of the casing 10 together with the refrigerant.
On the other hand, in order to remove the gap generated between the oil guide 90 and the upper end ring 81 according to the assembling tolerance or the processing tolerance of the balance weight 110 and the oil guide 90, if the balance weight 110 is formed to be integrated with the oil guide 90, the balance weight 110 and the oil guide 90 are generally fabricated using copper, considering that the balance weight 110 is generally fabricated using the copper. Accordingly, the fabrication cost can be increased.